Tyrelli was a star system located somewhere in the space of the galaxy's Alpha or Beta Quadrants.
History and specifics
The Tyrelli system's orbit was the location of at least one planet, Tyrellia.
In the year 2268, a merchant at Wagner Trading Post sold Tyrellian knives. James T. Kirk, Spock, and Leonard McCoy haggled for one. When the vendor offered a low price, Spock wondered if it had been smuggled out of the Tyrelli system. (TOS novel: Dreams of the Raven)